Most shops know they waste something and almost none know how much. The cost hides inside 'the stock number looks low again' and never appears as its own line, so it is never managed.
Recording a reason is what makes the data useful. 'Expired' points at over-ordering; 'damaged' points at storage or handling; 'internal use' is staff meals that should be budgeted rather than discovered. Same quantity, three entirely different fixes.
Wastage is also a control issue, which is why it should require a reason and leave an audit trail. A stock write-off is one of the simplest ways to cover a shortage, so an untracked adjustment facility is a gap worth closing.
Outale logs wastage with quantity, reason and notes, keeps a full chronological history of every stock change, and reports the cost of written-off stock alongside sales so it can be read as a real expense.